Francini A, Galleschi L, Saviozzi F, Pinzino C, Izzo R, Sgherri C, Navari-Izzo F
Dipartimento di Scienze Botaniche, Università di Pisa, via L. Ghini 5, 56126 Pisa, Italy.
Plant Physiol Biochem. 2006 Oct;44(10):556-63. doi: 10.1016/j.plaphy.2006.09.002. Epub 2006 Sep 25.
The changes in several antioxidants as well as in the level of C-centered free radicals and thiobarbituric acid reactive substances (TBARS) were studied in seeds of Araucaria bidwillii Hook desiccated to 37%, 28% and 21% moisture content. The lowest-safe moisture content for the seedling establishment was 37%. The embryo, besides double amounts of free radicals, showed higher levels of both enzymatic and non-enzymatic antioxidants than endosperm. Lutein decreased in both organs whereas alpha-tocopherol values were not affected by desiccation. In the embryo at 37% seed moisture content the antioxidant defense system increased giving rise to a decrease in free radicals. Beyond this point, free radicals and TBARS increased in agreement with the umpiring of the ascorbate/glutathione cycle by the decrease in reduced glutathione and glutathione reductase activity (GR, EC 1.6.4.2). At 21% moisture GR decreased. In the endosperm during desiccation, the consumption of ascorbate, total glutathione and lutein prevented the rise in free radicals and TBARS till 28% moisture, at which an increase in oxidized glutathione was also observed.
研究了干燥至水分含量为37%、28%和21%的南洋杉种子中几种抗氧化剂以及C中心自由基和硫代巴比妥酸反应性物质（TBARS）水平的变化。种子萌发的最低安全水分含量为37%。胚除了自由基含量加倍外，其酶促和非酶促抗氧化剂水平均高于胚乳。叶黄素在两个器官中均减少，而α-生育酚值不受干燥影响。在种子水分含量为37%时，胚中的抗氧化防御系统增强，导致自由基减少。超过这一点，随着还原型谷胱甘肽和谷胱甘肽还原酶活性（GR，EC 1.6.4.2）降低，抗坏血酸/谷胱甘肽循环失衡，自由基和TBARS增加。在水分含量为21%时，GR降低。在胚乳干燥过程中，抗坏血酸、总谷胱甘肽和叶黄素的消耗在水分含量达到28%之前阻止了自由基和TBARS的增加，在28%水分含量时还观察到氧化型谷胱甘肽增加。
